Different types of acoustic devices have been used through the years. One type of device is a microphone and one type of microphone is a microelectromechanical system (MEMS) microphone, including a MEMS die having a diaphragm and a back plate. The MEMS die is supported by a substrate and enclosed by a housing (e.g., a cup or cover with walls). A port may extend through the substrate (for a bottom port device) or through the top of the housing (for a top port device). In any case, sound energy traverses the port, moves the diaphragm and creates a changing potential of the back plate, which creates an electrical signal. Microphones are deployed in various types of devices such as personal computers or cellular phones.
Digital microphones now exist that convert the analog data produced by the sensor into digital data. The digital data is utilized by different processing elements in the microphone to perform different sets of functions such as acoustic activity detection. Acoustic activity detection requires time to be performed in a reliable manner. Unfortunately, this time delay in detection incurs latency, which allows real-time data to pile or back-up thereby reducing the efficiency and performance of the system. The latency further requires use of a buffer to store audio data, while the acoustic activity detection is made.
The problems of previous approaches have resulted in some user dissatisfaction with these previous approaches, specially the latency that is incurred and that stays in the audio path impacting user experience in voice recognition tasks.
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